The standard production process for producing helically wound metal pipe is well known. Elongated metal sheet strip material is spiraled into a helical form so that opposite edges of the strip come together and can be crimped to form a helical lock along the pipe. In some cases, the metal sheet strip may be flat when spiraled. In other cases, lengthwise extending corrugations, ribs and/or channels may be formed in the elongated metal sheet prior to spiraling for increasing the strength of the pipe. One example of a platform mill for producing such helical pipe is shown in U.S. Pat. No. 7,404,308.
In some applications it is desirable for the resulting pipe to be sealed. Welded locks are sometimes used for this purpose, but such welding tends to increase cost. It is also known to provide liners in the resulting pipe, which can again be costly.
It would be desirable to provide a helically wound pipe with helical lock and an associated sealing arrangement that is cost-effective.